Long seed, short pump: converting Yb-doped laser radiation to multi-µJ few-cycle pulses tunable through 2.5–15 µm

Abstract

We present a setup for generating broadband (up to 1050 cm −1 ) and broadly tunable (2.5-15 µm) mid-infrared pulses using an Yb-doped femtosecond laser as the pump source. Our scheme, comprising two parametric amplifiers and a mixing stage, exploits favorable group velocity matching conditions in GaSe pumped at 2 µm to directly produce sub-70 fs pulses throughout the tuning range without any additional dispersion compensation, while 30–50 fs pulse durations are achieved with simple dispersion compensation by propagation through thin bulk media. The generated pulses have sub-1% short- and long-term energy noise, as well as stable spectral parameters, while delivering 0.5–2 W average mid-IR power. We expect the source to be useful for various spectroscopic applications in the mid-IR.